This invention generally relates to systems and methods for re-routing an airborne vehicle when a potential loss of separation from another airborne vehicle has been determined.
Loss of separation between aircraft occurs whenever specified separation minima are breached. Minimum separation standards for airspace are specified by Air Traffic Services (ATS) authorities, based on FAA (Federal Aviation Administration) standards.
The problem to be solved is to assure separation for a single aerial vehicle against one other aerial vehicle, where both vehicles are en-route and a potential loss of separation (LOS) has been calculated.
The existing solutions are as follows: (1) human intervention, e.g., a traffic controller predicts a loss of separation and directs the vehicle controller how to prevent it; (2) Traffic Alert-Collision Avoidance System (TCAS), which predicts an unsafe separation and generates either an alert or avoidance instruction to the vehicle controller to change altitude.
In the case of human intervention, neither a traffic controller nor a remote pilot provide an on-board capability to avoid other aircraft, which is important when data links fail. TCAS uses altitude changes instead of a lateral maneuver. Air traffic rules dictate that unmanned systems will follow right-of-way rules that not only prescribe a lateral maneuver, but disallow altitude changes for separation. FAA CFR 91.113 (b) states: “When a rule of this section gives another aircraft the right-of-way, the pilot shall give way to that aircraft and may not pass over, under, or ahead of it unless well clear.” Also altitude changes have a weakness for a see and avoid capability when the sensor meets the minimum field of regard requirements set forth in F2411-07, Standard Specification for Design and Performance of an Airborne Sense-and-Avoid System. The required field of regard does make all potential threat aircraft vehicles visible. A simple example would be two aircraft following the same ground track at separate altitudes. Also TCAS does not return the vehicle to its original vector as required by F2411-07, Section 4.3.5.3.
There is a need for a solution that avoids the disadvantages of the foregoing existing solutions.